92 Immigration of Animals and Plants. 
eee marginatum, Asparagus officinalis, Hemerocallis fulva, and Setaria 
italica. 
Now all the really naturalized plants form, indisputably, part of our flora, 
just as well as the immigrated white people, as soon as they acquire their paper 
of naturalization, form a part of the nation. The difference is onlyintime. All 
the white people have immigrated within three centuries, and all our Illinois 
plants have immigrated after the drift period to this day. All things change, 
but the change of our immigrated plants is not so retrograde as Lyell means, 
when, in his second visit to the United States, speaking of introduced plants, 
he remarks: “It is a curious fact, which I afterwards learned from Dr. Dale 
Owen, that when such foreigners are first naturalized they overrun the country 
with amazing rapidity and are quite a nuisance; but they soon grow scarce, 
and after eight or ten years can hardly be met with. 
We wish only that might be so in regard to the rats and mice, the cock- 
roaches and bed-bugs. - 
THE LIBRARY GF THE 
FEB 18 1937 
UNIVERSITY OF ILLINOIS 
